This round enables a projectile to be fired, but without imparted spin, from a M203/M320 grenade Launcher. This is an achievement since the barrel of the M203/M320 is rifled, which ordinarily would spin up a projectile (such as the typically used M433 HE Dual Purpose projectile) as it travels down the barrel tube, and the projectile would leave the gun tube with a high spin rate, for spin stabilization. Eliminating this spin is an achievement because the projectile could then be fitted with guidance/control which would greatly enhance the performance of the projectile. However, to add such guidance/control the projectile must not be spinning. Instead, fins will subsequently be used here (after launch) for fin stabilization.
The M203/M320 are not stand alone gun launchers, but are used by attachment to an M16 or M4 rifle, for instance. They can then fire a family of 40 mm low velocity projectile rounds. In order to load a 40 mm round into an M203, the forward sleeve of the gun tube is slid forward, and a 40 mm round is pushed into the sleeve. The sleeve is then slid backwards and locked into position, ready to fire. The barrel of the M203 is rifled, which spins up the projectile as it travels down the barrel tube, and the projectile leaves the gun tube with a high spin rate. The area of rifling is approximately six inches in length.
Projectiles currently used in M203/M320 grenade launchers include the M433 High Explosive Dual Purpose Round, the M406 High Explosive Round, M583A1 Star Parachute Round, M585 White Star Cluster Round, M713 Ground Marker Round, M781 Practice Round, M651 CS Round, and the M576 Buckshot Round.
The 40 mm cartridge case is typically not reused or recycled after firing. If the cartridge case becomes stuck in the gun tube, there is a tool to help the war-fighter push it from the tube. The M320 fires the same 40 mm low velocity ammunition as the M203. There are several improvements that the M320 has compared to the M203. The M320 has stand alone single shot capability and may be fired by the war-fighter without attaching to a gun. it also has the capability to be attached to and fired from the M16/M4 rifle, similarly to the M203. A major improvement of the M320 is the ability of the firing tube to open sideways. By opening sideways, longer ammunition can be loaded into the M320 gun tube as compared to loading in an M203. While the approximate maximum length of the projectile is approximately five inches in the M203, projectiles several inches longer can be loaded into an M320. Both M203 and M320 have rifled barrels which induce spinning in the projectile as it travels through the gun tube.
There exists a great need to develop a new family of 40 mm projectiles that can extend range through increased velocity and projectile shape to over 1000 meters; to have the capability for adding on optional guidance navigation and control features/components; to increase projectile length to accommodate more lethal fragments and increased amount of explosive and energetic; and; to increase lethality through enhanced precision and more accurate strikes. At the same time, it is necessary to provide a training projectile that flies similarly to the tactical projectile, which will allow a war-fighter the opportunity to train with a realistically similar flying projectile that performs analogously to its actual tactical projectile equivalent. The training projectile can also be equipped with an inert florescent powder where upon ground or target impact, the projectile releases the powder to imitate an explosion. When the projectile is needed for battle, it is equipped instead with a fuze, explosive, shape charge liner and/or warhead, and it is equipped to defeat a target upon impact. Additionally, optional guidance and control components/features can be added to the front or side of this projectile utilized for battle. The optional guidance and control features provide increased accuracy and more precision hits on targets up to and beyond 1000 meters (a goal which is sought). Guided ammunition would need to have no spin (or very little spin) so that the seeker or camera therein, for instance, can see the target clearly while in flight. The conventional M203 or M320 grenade launcher guns have internal rifling intended to spin up the projectiles (at approximately 1800 revolutions per second) for stabilization of flight. Clearly then, a way must be found to avoid the spin which is inherent in conventional M203 or M320 grenade launcher guns when optional guidance is desired to be added to the projectile.